| 题名 | 铝团簇电子结构和稳定性的尺寸演化 |
| 作者 | 翟华金 |
| 学位类别 | 博士 |
| 答辩日期 | 1999 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 王育竹 |
| 关键词 | 铝团簇 混合／掺杂团簇 质谱 电子壳层结构 奇偶交变 紧束缚局域轨道理论 |
| 中文摘要 | 论文研究含微量碳、氧、水杂质特殊源条件下铝团簇及其掺杂／混合系列的质谱特性以及随杂质浓度的演化。观察到 Al_N~- (N=3～21)质谱的强烈奇偶交变，并首次观察到 Al_7O~- 处2s电子壳层和 Al_(37)~- 处3p电子壳层。在掺杂中性团簇光电离质谱中观察到 Al_7C，Al_(13)C，Al_9(H_2O)_m(m = 1，2)，Al_(11)O 等局域极大，以及特殊稳定的富氧混合系列Al_5O_3、Al_7O_4、Al_9O_7，提出富氧混合团簇形成的融合机理，并予实验验证。理论上发展Anderson-Bullett紧束缚局域轨道方法于小尺寸铝团簇电子结构的描述，发现s-p杂化临界尺寸以下铝团簇的s-p带隙随尺寸表现为“非凝胶-凝胶阻尼振荡”。 |
| 英文摘要 | This thesis summarizes mainly our experimental studies on aluminum clusters using laser vaporization and pulsed molecular beam techniques, while a localized-orbital theory basing on the tight-binding approximation is also developed. The main results are as follows: (i) A pronounced odd-even alternation is observed for Al_N~- (N = 3～21), where even-numbered Al_N~- disappear completely. The 2s electronic shell closing at Al_7O~- and the 3p electronic shell closing at Al_(37)~- are demonstrated for the first time. (ii) A unified picture characteristic of the coexistence of valence-electron-pairing effect and geometrical effect for the odd-even alternation of aluminum clusters is put forward. (iii) For the neutral clusters channel, Al_7C, Al_(13)C, Al_9(H_2O)_m(m = 1, 2) , and Al_(11)O are observed as local prominent peaks, and an oxygen-rich series Al_5O_3, Al_7O_4, and Al_9O_7 with special stability is reported, a fusion mechanism is suggested for their formation. The fusion mechanism is supported by direct experimental evidence. (iv) The Anderson-Bullett tight-binding method is developed to describe the size-dependence of electronic structure of small aluminum clusters. It is revealed that magic-numbered clusters exhibit each a HOMO-LUMO gap maximum, and simultaneously an s-p gap minimum, but not necessarily an ionization potential maximum. It is also found that even below the critical size of s-p hybridization, the s-p gap exhibits a "nonjellim-jellium damped oscillation", rather than a simple nonjellium-to-jellium transition. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15535]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 翟华金. 铝团簇电子结构和稳定性的尺寸演化[D]. 中国科学院上海光学精密机械研究所. 1999. |
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